CHINO, Calif.  The record rains in Southern California have done heavy damage to the dairy industry, killing or sickening cows and leaving herds udder-deep in mud and cold water.

Many farmers are watching their cows die from exhaustion and exposure.

Dairy farmers said the drenching has cost the Southern California industry at least $38 million in lost milk production, dead and sickened animals, and damage to holding ponds and other flood-control features on their farms.

In many cases, the farmers are unable to do much to remove the standing water, because of strict environmental laws regulating dairy-farm runoff, which is usually fouled with manure.

"We have nowhere to go with the water, the ground is soaked. Our dairies aren't designed to deal with this," said Art Marquez, a third-generation dairy farmer in this community about 40 miles east of Los Angeles. Marquez has 4,000 cows at two dairies and said he has lost at least $2,000 a day to the rain over the past few weeks.

Normally, the region receives about 14 inches of rain in the entire winter season, but this year it has registered more than 30 inches since October, he said.

Cows produce less milk when they have to expend so much energy slogging through water. Also, cows resist lying down in standing water and will stand for days in the soggy muck until they collapse _ and sometimes die _ from exhaustion.

In a normal rainy season, each dairy farmer in the region usually loses about two cows a month to exhaustion and disease. The 250 dairies this year in the region are losing about a cow a day.

The Southern California dairy industry consists of San Bernardino and Riverside counties, both of which are east of Los Angeles. They have about 250 dairies with 200,000 cows, and accounted for about 6 billion gallons of milk and $760 million in revenue in 2004.

The economic hit to the region is the worst since 1997, an El Nino year when dairy farmers lost about $60 million and the area was declared a federal disaster area, said Robert Feenstra, executive director of the Chino-based Milk Producers Council.

Bill VerBoort, general manager of the California Dairy Herd Improvement Association, said the troubles will probably not affect milk prices in the area's supermarkets, because Southern California's dairies do not represent enough of the industry to affect the market. Still, farmers fear prices will go up.

Feenstra said the council has provided its loss estimates to Washington, and the farmers hope to receive federal aid.

"The damage is so devastating, farmers aren't going to be able to survive without some help," he said. "The mud and the mire is several feet deep and it's getting worse every day. A lot of the facilities are overflowing with water."